Republicans have seized on the latest developments in the Hillary Clinton email controversy as an issue that could help Donald Trump make up ground in the final US presidential debate.
It follows news that the US state department had asked FBI officials to lower the classification of a sensitive email related to the attack on the US compound in Benghazi, Libya.
FBI notes released on Monday revealed discussion of a “quid pro quo” in trying to get the email reclassified, though both the state department and FBI officials deny any bargaining took place.
Mr Trump called it “one of the great miscarriages of justice” in history.
But with Wednesday’s debate approaching, Mr Trump and his campaign have had trouble sticking to the message.
The candidate has continued his controversial warnings that the election is “rigged”, angering his fellow Republicans who worry his rhetoric will hurt public faith in elections.
And as news about the emails hit, Melania Trump made her first public comments about the allegations of sexual assault and misconduct lodged against her husband.
In an interview with Fox News, Mrs Trump said she believes the accusations were co-ordinated by political rivals: “They want to damage the presidency of my husband, and it was all planned, it was all organised from the opposition.”
Mr Trump’s comments carried echoes of Mrs Clinton’s allegations of a “vast right-wing conspiracy” organised to raise similar allegations against her husband two decades ago.
Mr Trump notably tried to revive Bill Clinton’s history by inviting his accusers to the last debate.
His guest list for Wednesday’s face-off in Las Vegas signalled he hoped to change the subject.
The Trump campaign said that Pat Smith, whose son Sean Smith was killed in the attack in Benghazi, will be attending the debate as the candidate’s guest.
Ms Smith was a featured speaker at the Republican National Convention, where she delivered an emotional speech blaming Mrs Clinton for her son’s death and accusing her of lying to families about what sparked it.
Mrs Clinton planned to spend Tuesday in New York preparing for the debate in Las Vegas.
Mr Trump was due to hold rallies in Colorado.
The disclosure of FBI documents revives questions about Mrs Clinton’s use of personal email during her time as secretary of state.
The issue has dogged her campaign and damaged voters’ trust in her even as she remains the favourite ahead of the November 8 vote.
The documents released on Monday show that a state department undersecretary for management, Patrick F Kennedy, a former close Clinton aide, contacted an FBI official seeking to change an email’s classification, a move that would have sent it to the archive, out of public view.
Notes on the conversation describe discussion about a “quid pro quo” in which the email’s classification would be changed and the state department would allow the FBI to place more agents in countries where they had not been permitted.
The records indicate that Mr Kennedy made that suggestion, but both the FBI and state department said that it was the unidentified FBI official. Neither the declassification nor the increase in agents occurred.
Clinton campaign allies argued that the documents show bureaucratic haggling.
“None of this has anything to do with Hillary Clinton. She wasn’t involved in this at all,” said Representative Jerry Nadler, a Democrat from New York and a Clinton ally.
Mr Nadler said “maybe” the conduct of the officials involved “should be looked at”. The news came as Mrs Clinton is trying to expand her edge over Mr Trump – even in Republican territory.
Her campaign announced it was launching a new push in Arizona, including a campaign stop in Phoenix by first lady Michelle Obama, one of Mrs Clinton’s most effective surrogates.
An additional one million dollars is going into efforts in Missouri and Indiana, both states with competitive Senate races, and a small amount of TV time is being bought in Texas and media appearances are scheduled in Utah.
On the other side, Mr Trump’s campaign dramatically expanded its ad buys in seven battleground states and announced plans to launch a two million dollar advertising blitz in long-shot Virginia.